.black{
    background: black;
    color: white;
    font: 20px;
    width: 100px;
    height: 50px;
}
.white{
    background: white;
    color: black;
    font:20px;
    width: 50px;
    height: 100px;
}
#div01{
    width: 200px;
    height: 200px;
    font: black;
}